Kartak is proud and desires to be recognized for his noble bearing and self-imposed importance. He refuses to associate himself with other undead unless it is necessary to, such as in his dealings with his fellow Twisted Rune members. He is also an unashamed psychopath.

A distant cousin from the main branch of the family known as Spellseer, he still carried the family name and lived in the family castle. He became involved in Spellseer business when, amidst false accusations from rival Amnian traders, he was accused of gruesomely murdering and experimenting on 14 young local men & women in order to perform a foul necromantic rite. The evidence was completely fabricated, but ironically the charges were all totally true. He was arrested at the castle in 830 DR, tried and sentenced to hang.
Kartak managed to escape his fate when a wizard named Rysellan the Dark and several associates broke Kartak (and 15 other convicts) out of jail with a ring of the ram. Kartak then escaped on horseback to the Kuldin Peaks.

It isn't known exactly when Rysellan took Kartak as one of his apprentices, but it is known that Kartak brewed and imbibed a potion that killed him and turned him to lichdom in 856 DR, hiding his phylactery in his former home, now known as Castle Spulzeer. He went on to be instrumental in helping to found the Twisted Rune 8 years later. Together with the other members of that organization they became one of the most powerful groups active in southwestern Faerûn. Of course, almost all large, evil organizations eventually fall to infighting and rather than expanding their powerbase further, the Rune turned on itself, splitting into warring factions. Kartak remained loyal to Rysellan and battled the other factions at his side for 170 years until Rysellan's faction came into a direct spell-battle with another one. They were outmatched and Rysellan, Kartak and another of Rysellan's apprentices were destroyed in 1188 DR.

Unlike the others who fell, the Rune didn't know where Kartak's phylactery was. Kartak also had the foresight to place a geas on his mortal servants that in the event of his destruction, they would seek out his remains and place them in a specially prepared sarcophagus that would allow him to exert some limited mind control over someone in the castle. It would take about 150 years before Kartak's mind could find someone who was both weak-willed and unfocussed enough for him to dominate. This person took the form of Chardath Spulzeer who, in 1348 DR succumbed to Kartak's influence and murdered his sister, Marble Spulzeer, in an arcane rite to reanimate the lich's corpse.

Kartak returned to the Kuldin Peaks and wreaked revenge on the remaining rebels in the Twisted Rune while increasing his magical powers and wallowing in the growing hatred he had started to feel towards his family. However, every year on the anniversary of Marble's death, Kartak found himself summoned to the site of the murder, unable to leave for 24 hours.